bio test 3 - lecture 2 Flashcards
(21 cards)
Which statement does not describe a reason why the lipid bilayer of your membrane can be called “fluid?”
- Because at the bonding it has hydrogen bonding and van der waal forces
- Proteins in it; phospholipids +transmembrane (integral) protein, and can move: physically, unanchored, weak polar heads.
The fluid mosaic model was created by Singer and Nicolson in 1972. That stated that the cell membrane is composed of a phospholipid bilayer. Which statement describes one of the functions of this lipid bilayer?
Flexible matrix to form all kinds of shapes
Able to form a barrier when needed: few things that can fit in and out the cell without chemical reaction, without carrier and channels
. The fluid mosaic model was created by Singer and Nicolson in 1972. That stated that the cell membrane contains transmembrane proteins. Which statement describes one of the functions of these transmembrane proteins?
Going all the way through, they can send different substances and chemical information across the membrane. Integral and peripheral proteins. They are selective and specific on what they send.
. The fluid mosaic model was created by Singer and Nicolson in 1972. That stated that the cell membrane contains an interior protein network. Which statement describes one of the functions of the interior protein network?
Interior protein network - Membranes are structurally supported by intracellular proteins that reinforce the membrane shape.
(These membranes can hook onto your cytoskeleton and can affect the shape of the cell and membrane.
Spectrins - the type of proteins that affects the concave shape of the red blood cells
The fluid mosaic model was created by Singer and Nicolson in 1972. That stated that the cell membrane contains cell surface markers such as glycoproteins and glycolipids. Which statement describes one of their functions?
Glycolipids are the flags found on your cell
Glycoproteins are the cell recognition and form the extracellular matrix for animal cells, and add extra protection and less permeability (ECM)
. Recent findings have discovered the plasma membrane is not homogeneous and contains microdomains with distinct lipid and protein compositions. These portions of the cell membrane are called _______ and are heavily enriched in cholesterol and saturated fatty acids which makes it “thicker” than other areas of the plasma membrane. (VERY noticeable under a microscope) (NOT HOMOGENEOUS) Fill in the blank.
. Recent findings have discovered the plasma membrane is not homogeneous and contains microdomains with distinct lipid and protein compositions. These portions of the cell membrane are called Lipid rafts and are heavily enriched in cholesterol and saturated fatty acids which makes it “thicker” than other areas of the plasma membrane. (VERY noticeable under a microscope) (NOT HOMOGENEOUS) Fill in the blank.
Which statement describes a possible function of a lipid raft?
Signal reception (Microdomains)
Cell movement (Microdomains)
Microdomains- areas that don’t look like any place else on the plasma membrane (function above)
(HIV targets these areas- medication blocks that from happening)
Proteins within the plasma membrane can be multifunctional. Which statement does not accurately describe the function of different transmembrane proteins?
Transporters: channels transporting in + out of , very specific
Enzymes: catalysts– responsible for chemical reactions,
Cell surface receptors
Accepts signal
Sends signal to nucleus “do response”
- Cell surface identity markers- usually glycolipids, and occasionally glycoproteins - glycolipids (max) + glycoproteins (min)
- Cell adhesion protein connecting two cells together
- tight junctions,
- Attachments to the cytoskeleton
- microtubule (sending back and forth, like a train track),
- intermediate filaments (wouldn’t budge),
- actin filaments (move back and forth)
What is the definition of simple diffusion?
Moving things from high to a low concentration gradient using no energy. (Not for water)
Which type of molecules can easily go and pass through the phospholipids bilayer of your cell membrane during simple diffusion (i.e. which type do not need a carrier or channel)?
Transmembrane proteins are the carriers and channels, they are only required when simple diffusion isn’t used (most cases)
These three do not need carriers and channels, and they just go through the membrane
Selective permeable only fits three specific things:
Most gasses
Hydrophobic molecules (must be small)
(small) Polar uncharged molecules
!! IF THEY AREN’T SMALL THEN THEY WILL NEED CARRIERS AND CHANNELS !!
The more you have the faster they travel; the less you have the slower. EXCEPT THESE THREE THINGS THEY ARE CONSTANT
In order to diffuse many different ions and larger molecules across the plasma membrane, your cell must use protein channels and carriers. Why is this the case (the definition of an ion channel we discussed in class is the hint)?
Ion channels- Area that possess’ a hydrated interior that spans the membrane. The diffusion of ions through channels
Cations- positively charged ions
Anions- negatively charged ions
If you want to use a carrier and channel you will have specific ones, positive charges would og to Cations, and negative charges go through Anions
You cannot have a properly functioning nervous system without your ions being controlled in the way they are.
What is the definition of passive transport? (hint…why is it called passive?)
How things are moved in and out of the cell without energy, that’s why it’s passive
. How is the direction of the net movement of molecules determined when simple diffusion is occurring? (hint…there are two answers we discussed in class)
Concentration gradient or voltage across the membrane
. Which statement does not describe one of the three characteristics of facilitated diffusion?
Facilitated diffusion: Moving things from high to a low concentration gradient using no energy, and using carriers and channels (Not for water)
3 characteristics:
It is specific- a given character can only transmit certain molecules and ions
It is passive- no energy requirements only works on a concentration gradient, type of passive transport
It saturates-
According to the video Diffusion, a concentration gradient is itself a form of _______ energy. Fill in the blank.
According to the video Diffusion, a concentration gradient is itself a form of potential energy. Fill in the blank.
According to the video Diffusion, ______________ is when molecules still have a net movement of high concentration to low concentration, but they may be too large or have other characteristics that prevent them from directly traveling across the selective cell membrane (they need to use a carrier or channel). Fill in the blank.
According to the video Diffusion, facilitated diffusion is when molecules still have a net movement of high concentration to low concentration, but they may be too large or have other characteristics that prevent them from directly traveling across the selective cell membrane (they need to use a carrier or channel). Fill in the blank.
. According to the video Diffusion, how can distance affect the rate of diffusion?
The greater the distance that needs to be traveled , the slower the diffusion rate.
According to the video Diffusion, how can temperature affect the rate of diffusion?
Higher temperature means there is more movement of the molecules, the diffusion rate is increased.
According to the video Diffusion, how can the characteristics of the solvent affect the rate of diffusion?
If the solvent is dense, it will slow the molecules down. Decreasing the diffusion rate
. According to the video Diffusion, how can characteristics of the substance traveling affect the rate of diffusion?
The greater the mass of the substance, there is a lower diffusion rate compared to the substance with less mass
. According to the video Diffusion, how can characteristics of the barrier affect the rate of diffusion?
Small and/or nonpolar substances pass through the membrane easier than substances that are large and/or polar
Large surface area and thin membrane allows a faster diffusion rate compared to a small surface area and thick membrane.
